A method and system for navigating a vehicle is already known from European Patent Application No. 715 289, a vehicle being guided by an on-board navigational system, on the basis of an on-board digitized street map, along a travel route determined by a traffic guidance system. Planning data are transmitted from the vehicle to the external traffic computer, in accordance with which a complete travel route, determined by the traffic computer, is transmitted to the vehicle. By comparing the current position with the travel route on the basis of the digitized street map, the navigation is performed in the vehicle by an on-board computer, which determines the appropriate travel instructions and which may announce them over a loudspeaker and optically via a display. To be able to output current travel instructions, it may be required in this context that the navigational device in the vehicle access a street map, which is either carried in the vehicle or is transmitted by the traffic guidance system. For the street map, a corresponding amount of storage space may be required. Furthermore, the arithmetic unit may be required to first determine the travel instructions for a driver from the transmitted route.